Rear Window Spoiler

hello can anybody help,i own a 55 ford c-max 2.0 tdci and have a very annoying rattling sound coming from the rear of the car,i have looked at everything but think i have tracked it down to the rear window spoiler there is plenty of movement with it,but i dont know how to remove it to check it,we have just had it in for a re-spray after an accident,and i personally believe they have not put it back on correctly or even worse broken some plastic luggs off,if this is the case i will make them sort it out,